A user interface, such as a set of controls, may be configured to allow a user to select directly a desired level for a parameter used by a system to perform some operation or produce some result. One example of such a control is a simple volume control on a consumer device such as a television or radio, which enables a user to select directly a desired level of loudness. A typical rotary or slider type volume control may comprise a potentiometer (variable resistor) configured as a variable voltage divider such that the position of the control determines directly the level of the input signal voltage that goes to the amplifier.
In some cases, however, there may not be a direct, one-to-one relationship between a user control and an internal parameter that is affected by the control. This may be the case, for example, whenever the user relates to an experience, such as hearing an audio signal as rendered, in a way that does not translate directly into the operations performed by the system being controlled via the user control, such as a digital signal processing system. In some cases, it may be necessary to generate values for two or more internal parameters based on a single externally provided control signal, such as a user input received via a user control or other interface. As a result, there is a need for a way to derive from an external control signal a set of values for one or more internal parameters.
In addition, one or more distinct processing modules may be used to perform different types of operations in response to an external control signal, such as an input received from a user via a user control. For example, a signal processing system may be configured to use one or more of a plurality of processing modules to process an audio (or other) signal. Such a system may provide to a user more than one control interface (e.g., a plurality of knobs, sliders, or other controls, or one or more controls for selecting a preset group of two or more separate settings) to enable a user to indicate a desired level of more than one desired quality of the signal as rendered. In some cases, a single control or setting may affect the internal parameter values for more than one processing module. It is also possible for two controls to affect the level of one or more parameters for the same processing module, possibly in ways that conflict. In such systems, there is a need for a way to combine and reconcile the potentially conflicting user inputs (or other control signals) to generate a combined set of parameters for the various processing modules.